We were really curious to see how much power this unit could really deliver, because by the project used we suspected it could deliver far more than what was labeled.

On the table below you can follow the several overloading tests we conducted.

Input	400 W	423 W	440 W	460 W	475 W
+12V1	14 A (168 W)	15 A (180 W)	15 A (180 W)	15 A (180 W)	15 A (180 W)
+12V2	14 A (168 W)	15 A (180 W)	15 A (180 W)	15 A (180 W)	15 A (180 W)
+5V	6 A (30 W)	6 A (30 W)	8 A (40 W)	10 A (50 W)	12 A (60 W)
+3.3 V	6 A (19.8 W)	6 A (19.8 W)	8 A (26.4 W)	10 A (33.3 W)	12 A (39.6 W)
+5VSB	2.5 A (12.5 W)	2.5 A (12.5 W)	2.5 A (12.5 W)	2.5 A (12.5 W)	2.5 A (12.5 W)
-12 V	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)
Total	400 W	422.8 W	440 W	457.8 W	475 W
% Max Load	111.1%	117.4%	122.2%	127.2%	131.9%
AC Power	500 W	536 W	564 W	594 W	623 W
Efficiency	80.0%	78.9%	78.0%	77.1%	76.2%

Let’s explain exactly what we did. First we tested to see if over current protection circuit was really enabled. In order to do that we conducted two tests. First we connected the main motherboard cable to our load tester and increased current on +12V1 until the power supply shut down. This happened at 17 A, so OCP on +12V1 was set at 16 A. Then we connected EPS12V connector back to +12V2 input from our load tester, configured +12V1 to pull just a small amount of current (1 A) and increased current on +12V2 until the power supply shut down. This again happened at 17 A, so both virtual rails had OCP up and running, configured to shut down the power supply if we pulled more than 16 A from any of these two rails.

During our overload tests we tried to pull 16 A from each rail at the same time but we couldn’t, the power supply would shut down, either because of the OCP circuit or because voltages were out of range and the OVP or UVP was entering in action. The maximum we could pull from the two +12 V rails at the same time was 15 A.

After setting them at 15 A we decided to pull more from +5 V and +3.3 V to see what was this power supply limit. We tried pulling a very high value on these two lines like 20 A each to see if this power supply had over load protection. The power supply wouldn’t turn on, but probably because voltages went out of spec and OVP or UVP entered in action, because this power supply does not have OPP – keep reading to understand how we know that.

The maximum we could set at +5 V and +3.3 V that kept the reviewed power supply still turning on was 17 A each. This made our power supply to deliver 517 W and consume 705 W from the wall, so efficiency was at 73.3%. The problem, however, is that after one minute the power supply died. When we opened it we tested all main components and to our surprise all tested ok, so no main semiconductor burned, and we couldn’t find what exactly burned (probably the transformer).

Because we could pull up to 44% over the power supply rated power, we know that this power supply didn’t have over load protection (OLP or OPP, these two acronyms mean the same thing).

During all our load tests noise level was within specs but we couldn’t capture the screens for you to see.

Short circuit protection (SCP) worked fine for both +5 V and +12 V lines.

This power supply is really quiet, even when delivering its full power.